Use 3.27 microversion when creating new style volume attachments

Now that we have version discovery support we can explicitly
request 3.27 when creating a new-style volume attachment. If the
3.27 microversion is not available, CinderAPIVersionNotAvailable
will be raised back up to the caller, indicating an old-style
attachment needs to be made.

The same is done when updating or deleting new-style attachments.

A TODO is left inline for update and delete since we should be able
to assume that if we're updating or deleting a new style attachment,
which is keyed off the BlockDeviceMapping.attachment_id field, that
3.27 is available and we can save ourselves a GET / call to Cinder.

Part of blueprint cinder-new-attach-apis

Change-Id: Icf8cda2c34dda9e7b56a586353842dd035b115cd

1 files changed, 5 insertions, 3 deletions

diff --git a/nova/volume/cinder.py b/nova/volume/cinder.py
index b2fa315128..cdb8474040 100644
--- a/nova/volume/cinder.py
+++ b/nova/volume/cinder.py
@@ -556,7 +556,7 @@ class API(object):
                     getattr(attachment, 'connection_info', None)
         """
         try:
-            return cinderclient(context).attachments.create(
+            return cinderclient(context, '3.27').attachments.create(
                 volume_id, connector, instance_id)
         except cinder_exception.ClientException as ex:
             with excutils.save_and_reraise_exception():
@@ -581,7 +581,8 @@ class API(object):
             representing the updated volume attachment.
         """
         try:
-            return cinderclient(context).attachments.update(
+            # TODO(mriedem): consider skipping the microversion discovery
+            return cinderclient(context, '3.27').attachments.update(
                 attachment_id, connector)
         except cinder_exception.ClientException as ex:
             with excutils.save_and_reraise_exception():
@@ -594,8 +595,9 @@ class API(object):
     @translate_attachment_exception
     def attachment_delete(self, context, attachment_id):
         try:
+            # TODO(mriedem): consider skipping the microversion discovery
             cinderclient(
-                context).attachments.delete(attachment_id)
+                context, '3.27').attachments.delete(attachment_id)
         except cinder_exception.ClientException as ex:
             with excutils.save_and_reraise_exception():
                 LOG.error(('Delete attachment failed for attachment '